Funnel heating device



Nov. 8, 1938. 1.. N. MARKWOOD FUNNEL HEATING .DEVICE Filed Sept. 24, 1936 'sive.

Patented Nov. 8, 1938 UNITED STATES PATENT OFFICE 8 Claims.

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) This application is made under the act of March 3, 1883, as amended by the act of April 30, 1928, and the invention herein described and claimed may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

The invention herein described is a means for effectively and simply heating a funnel. Many operations of a chemist or laboratorian require that the funnel through which solutions areto be'filtered be heated during the operation of filtration. This is especially true in the field of organic chemical preparations where a frequent standard procedure is to filter hot concentrated solutions of an organic compound dissolved in a solvent such as alcohol, toluene, chloroform, etc. Unless the solution be maintained hot during filtration a portion of the solute will separate out, thereby clogging the filter and totally preventing the passage of the fluid.

Several devices for heating funnels are known. Some of these consist of rubber or metal coils wrapped around the funnel, through which hot water or steam is passed. Others are of the metal-jacket type, wherein an air chamber is heated by gas heat, or where a body of water enclosed in a double-walled jacket is heated by a gas burner under the funnel. Still another type consists of a double-wall all-glass funnel in which the outer wall is permanently sealed to the funnel proper.

All these types are awkward and cumbersome, as well as expensive, and the efficiency of heat transfer in most cases is low. Furthermore, the use of gas-heated devices is always dangerous in the presence of flammable solvents, which are commonly used in chemical operations.

These disadvantages do not exist in the present device. 'It is small and compact, taking up but little more space than the funnel itself, and is of such simple construction as to be inexpen- The efficiency of heat transfer from the heated medium-be it steam, hot Water, or other hot fluidto the funnel, is high because, as is shown in the drawing, the heat transfer medium comes in direct contact with the funnel. As a result the funnel is heated to practically the temperature of the medium in a very short time, and the funnel temperature is maintained at this degree of heat throughout. Other advantages, such as detachability, non-breakableness, and adaptability to filter flasks will be apparent from the construction.

The device is made preferably of rubber, but it may also be made of any other suitable material, such as Duprene, asbestos, metal, glass, or compositions of material which are resistant to the heating medium. In constructions other than a resilient material like rubber, the device is suitably gasketed to the inner funnel to provide a tight connection.

The construction and manner of fitting will readily. be understod by reference to the drawing, in which:

Figure 1 is a cross-section of the device or attachment, made of rubber, with the funnel inserted in position;

Figure 2 is the top view of the device;

Figure 3 is a cross-section of a modified form open at the bottom, to be used in combination with a resilient connection, and further explained below;

Figure 4 is a cross-section of a modified form made of non-resilient material, to be used in combination with resilient gaskets, and further explained below; and

Figure 5 is a cross-section illustrating an alternate suitable shape of the rim of the device for providing closure at the upper end of the funnel.

Similar numerals refer to similar out the several views.

The thickness of the wall I is sufficient to impart strength and permit resilience, being approximately A". The inside wall 2 is spaced at a distance from the funnel of approximately 4''. The lower end 3 consists of the usual stopper form of rubber stopper with a hole to make a snug fit between rubber and stem of funnel. The top is open to receive the bell of the funnel and make a tight connection therewith by means of the flange or rim 5, which is rounded or may be of any cross-section so as to make a fluid-tight connection. A section of suitable design for this purpose is shown in Figure 5. Inlet and outlet nipples 6 and 6' for the heat transfer medium are provided as shown, although they may be disposed relative to each other in other ways, for example, on the same level for gaseous fluids. These nipples are of rubber integral with the main body of the device. The inside height 1 of my device is so chosen that the rim 5 comes close to the rim of the glass funnel 4 while the pit 8 comes just below the steam juncture 9 of the glass funnel 4. In this way practically the entire outer surface of the glass funnel 4 is subjected to the heating medium, and, it is emphasized, the hot medium impinges directly against the funnel 4. The bore ID of the lower part 3 is of such diameter as to make a fluid-tight friction seal with the stem of the funnel. The external diameter H of the lower part 3 may be of any suitable magnitude from a size slightly greater than I I! to one several times greater. Since the lower part 3 is adapted for entrance into a filter flask, for filtration under reduced pressure, the diameter ll may be of such size as will be accommodated by the filter flask. But since there is a variparts throughstem diameters.

whereby tight connection can be made with any All parts of the device shown in Figures 1, 2, 3 Q

and 5, are made of rubber or other resilient material and it is formed or molded preferably in one piece, except that in Figure 3 a connection I3 is included. Its resistance to hard wear is thus insured. To attach the device to a funnel the stem of the latter is simply inserted downward into the bore of the part 3 until the outer funnel surface and the rim 5 make tight contact. By virtue of the resilient nature of rubber and the compression set up by the frictional ,re-

sistance of the stopper bore on the stem of the funnel, no escape of heating fluid occurs. The device is self-locking. It is understood thatany grade of rubber or similar elastic materialwliich has the necessary strength may be employed. stood that slight structural modifications may be resortedto, such as the inclusion of horizontal or vertical ribs in. the conical portion of the device to impart added strength or tighter fit;

Figure 3 in the drawing illustrates. a crosssection of a modified 'form of the device, fitted with afunnel 4 whereinthe lower part 3 iseliminated leaving the openend l2 into whichis inserted a separate connection [3; This manner of construction is advantageous where the device is .to be'used'vvith funnels having quite diffe ent ,A different connection 13 of suitable bore can be employed for each funnel. The connection 13 serves the triple purpose of providing the seal between the inner surface of the .flange l4, and the funnel stem 9; carrying the. stem '9 of'thefunnel 4; and connecting with the filter flask (not shown). When the connection l3. carrying the funnel stem v$1 is pushed into the opening iii a fluid-tight chamber is formed about the funnel 4.

Figures 1, 2, 3, and5v illustrate a funnel-heating device of the'nature described which is made of rubber .or other resilient material. The same form or pattern may also be utilized as stated with suitable non-resilient materials, such as metal, asbestos, glass,.or compositions, such as Bakelite. In these casesrubber or otherresilient gasketsare provided'at top and bottom 'to make fluid-tight joints with the glass funnel. These gaskets may be permanently joined to the con-.

tigucus part of.=the device or may be detachable;

Figure 4 shows a cross-section of such a device made of metal, with the inner funnel in position. The nipples l5 and [6f are made of the samemetal as the conical part ll and are a-flixed V thereto. The rubber'connection It serves ;t oclose the opening I9. and 'to carry the funnel stem. By increasing the length of s'aidjconnection 18 it 509.11 also serve :to connect with -a fllterj'flask (not shown). second rubber connection '20 with a hole: bored ingit to carry "the outer surface of the flange 2;l is provided for this purpose. I Theobjectin providing this double connectionarrangement is to shorten the stem .andgsole'ssen the possibility of crystallization from the liquid afterithe latter passes the zone of directheat. A rubber gasket 22, similar to an ordinary rubber band,,isqdrawn resilience, rigidity, .and'

It. is also under- However, more advantageously, a

around the upper rim 23 and provides the cushioning effect for metal against glass, as well as effectively sealing in the heated fluid.

Having thus described my invention, what I claim for Letters Patent is:

I claim:

1; A heat transfer device, comprising a substantially conical receptacle of resilient material, having openings formed therein, and inlet andoutlet means formed therewith, and adapted to hold a funnel and to substantially restrict theflow of circulating fluid between said receptacle and a funnel.

' 2. In a heat transfer device having a substantially conical receptacle of resilient material with openings formed therein, and inlet and outlet means formed therewith, and adaptedto hold.

a funnel and to control the circulation of heated fluid between said receptacle .and 'a funnel, and, an integral connection at the basal terminus of said receptacle.

3. In a heat transfer device having a substane tially conical receptacleof resilientmaterial with openings formed therein, and inlet and outlet means formed therewith, and adapted to hold;

a funneland to control the circulation of heated fluid between said receptacle and a funnel, and adapted to carrya connection at the basal terminus of saidreceptacle.

a. A funnel-heating device of resilient material capable of confining an externally heated circulating fluidin directcontact with said funnel.

by closure between contiguous portions of said;

device and said funnel,.closure being maintained by the natural resilience of the material of said;

viding an annular space between saidiunnel and said jacket, resilient means for hermetlcally sealing said funnel to said jacket at the upper rim of said'jacket and at the stem of said funnel,

and means for circulating a fluid in said annular.

space.

,. *2. In combination with a funnel, afunnel heat ing device comprising a conicaljacketof a nonresilient material adapted to be disposed'aboutv the outer surface of said funnel, a resilient-gasket between the upper rim of said jacket and the bell of said funnel, and a resilient connection between said jacket and the stemof saidfunnel,

an inlet and an outlet for circulating a fluidv between said jacket and saidfunnel.

8. A funnel heating device comprising a sub stantially non-resilient jacket adapted to bedisposed about the outer surface .of aufunnel pro; viding an annular space between said funneland said jacket, and resilient means for'removably;v sealing the bell and stem of said funnel tothe' upper rim and lower portion-of saidjacket, re

spectively, and means for circulating-a fluid in said annular space.

- LOUIS N. MARKWOOD. 

